Nitric oxide therapies

ABSTRACT

A method for delivering nitric oxide therapy to a subject can include administering a composition including a nitric-oxide releasing agent and silica to the subject and releasing a therapeutic amount of nitric oxide from the composition.

CLAIM OF PRIORITY

This application claims the benefit of prior U.S. ProvisionalApplication No. 61/219,200, filed on Jun. 22, 2009, which isincorporated by reference in its entirety.

TECHNICAL FIELD

This description relates to methods of treatment.

BACKGROUND

The inhalation or topical exposure of nitric oxide gas to a subject canbe beneficial in promoting healing of a wound, preparing a wound bed forfurther recovery, reducing infection and inflammation, and treatingpulmonary disorders. However, typical nitric oxide (NO) therapiesinclude compositions that may be toxic to a subject and can be difficultto administer.

SUMMARY

In general, a method for delivering nitric oxide therapy to a subject aninclude administering a composition including a nitric-oxide releasingagent and silica to the subject and releasing a therapeutic amount ofnitric oxide from the composition. In certain circumstances, silica gelcan prevent toxic compounds from entering the subject. In othercircumstances, the composition further includes an antioxidant. Theantioxidant can be ascorbic acid, alpha tocopherol, or gamma tocopherol.

In certain circumstances the composition can be in the form of anointment. In other circumstances, the composition can be incorporatedinto an adhesive strip. The adhesive strip can optionally include a foilbacking to prevent nitric oxide from being released into an externalenvironment. In some circumstances, the adhesive strip can have acalibrated scale on one surface thereof for accurate measurement of anointment dosage.

In certain circumstances, a composition can be in the form of a gum orlozenge. In other circumstances, the composition can be incorporatedinto a gas delivery device such as an inhaler or nasal cartridge.

In some circumstances, a therapeutic amount of nitric oxide is at least1 ppm, at least 100 ppm, at least 200, or at least 300 ppm.

A composition for delivering nitric oxide therapy to a subject caninclude silica and a nitric oxide-releasing agent. The agent can be apolymeric composition having a polymer and at least one nitric oxidereleasing N₂O₂ ⁻ functional group. The agent can also be selected fromthe group consisting of X

N(O)NO] and [N(O)NO

X.

A method for manufacturing a nitric oxide therapy to a subject caninclude incorporating a therapeutic amount of a nitric oxide-releasingagent into a silica composition into a delivery device. The deliverydevice can be an inhaler, an adhesive strip, an ointment, a gum, or alozenge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a gum or lozenge containing a composition anitric-oxide releasing agent and silica.

FIG. 1A illustrates one embodiment of a conversion cartridge 104 thatgenerates NO from NO₂.

FIGS. 2 and 3 illustrate an inhaler or nasal plug that contains anitric-oxide releasing agent and silica.

FIG. 4 illustrates an adhesive strip containing composition thatincludes a nitric-oxide releasing agent and silica.

FIG. 5 illustrates an adhesive strip containing composition thatincludes a nitric-oxide releasing agent and silica.

DETAILED DESCRIPTION

Various embodiments are directed to methods, compositions and devicesfor nitric oxide (NO) therapies. Generally, nitric oxide (NO) istopically applied, inhaled, or otherwise delivered to the individual'slungs. Providing a therapeutic dose of NO can provide several benefitsincluding reducing microbial infection, reducing inflammation,regulating the formation of collagen, and treating pulmonary disorders.In addition, a therapeutic dose of NO can be used to supplement orminimize the need for oxygen therapy or rapid descent to lowerelevations to treat symptoms of high-altitude sickness. A therapeuticdose of NO may be used without inducing toxicity to a subject. Forexample a concentration greater than 1 ppm, greater than 100 ppm, orgreater than 200 ppm can be used.

FIG. 1 illustrates a shell A, such as a gum or lozenge, the shellcontaining a therapeutic amount of a composition B, wherein thecomposition a nitric-oxide releasing agent and silica. The compositioncan be contained in the shell as shown, or alternatively, incorporatedinto the shell itself.

FIG. 1A illustrates one embodiment of a conversion cartridge 104 thatgenerates NO from NO₂. The conversion cartridge 104 also may be referredto as a NO generation cartridge, a GENO cartridge, or a GENO cylinder.The conversion cartridge 104 includes an inlet 105 and an outlet 110. Inone embodiment a particle filter 115 are located at both the inlet 105and the outlet 110, and the remainder of the cartridge 104 is filledwith a surface-active material 120 that is soaked with a saturatedsolution of antioxidant in water to coat the surface-active material. Inanother embodiment, the particulate filter 115 may be in the form of twoconcentric annular filters with the surface-active material 120 placedbetween the two annular filters. In this embodiment the gas flows fromthe inside of the annulus to the outside, or vice versa. In anotherembodiment, the surface-active material 120 and the filter material 115are cast into one solid matrix as a sintered tube. In the example ofFIG. 1A, the antioxidant is ascorbic acid.

FIGS. 2 and 3 illustrate an inhaler or nasal plug that contains anitric-oxide releasing agent and silica. The composition can becontained in the inhaler or nasal plug, or alternatively, incorporatedinto the inhaler or nasal plug itself.

FIG. 4 illustrates an adhesive strip 10 containing composition thatincludes a nitric-oxide releasing agent and silica. The composition canbe an ointment or salve embedded into a pocket 12 on a surface 11 of theadhesive strip. The adhesive strip can include calibrations 16 and 17that can be used to select or indicate the amount of ointmentadministered. The pocket can be a distance 21 from the perimeter of theadhesive strip.

FIG. 5 illustrates an adhesive strip wherein a composition such as anointment or salve is embedded into a pocket 12 of the adhesive strip,the adhesive strip having calibrations 16 and 17 that can be used toselect or indicate the amount of ointment 18 administered. The adhesivestrip can include a foil backing 12A, that can prevent NO or NO₂ frombeing released into an external environment.

NO can be created from different processes and releasing compositionsthat are discussed, for example in U.S. patent application Ser. No.11/206,305, which is incorporated by reference herein. Referring to FIG.1A, in a general process for converting NO₂ to NO, an air flow havingNO₂ is received through the inlet 105 and the air flow is fluidlycommunicated to the outlet 110 through the surface-active material 120coated with the aqueous antioxidant. As long as the surface-activematerial remains moist and the antioxidant has not been used up in theconversion, the general process is effective at converting NO₂ to NO atambient temperatures.

The inlet 105 may receive the air flow having NO₂, for example, from apressurized bottle of NO₂, which also may be referred to as a tank ofNO₂. The inlet 105 also may receive an air flow with NO₂ in nitrogen(N₂), air, or oxygen (O₂). The inlet 105 may also receive the air flowhaving NO₂ from an air pump that fluidly communicates an air flow over apermeation tube 235 containing liquid N₂O₄. The conversion occurs over awide concentration range. Experiments have been carried out atconcentrations in air of from about 0.2 ppm NO₂ to about 100 ppm NO₂,and even to over 1000 ppm NO₂.

In one example, a cartridge that was approximately 5 inches long and hada diameter of 0.8-inches was packed with silica gel that had first beensoaked in a saturated aqueous solution of ascorbic acid. Other sizes ofthe cartridge are also possible. The moist silica gel was prepared usingascorbic acid (i.e., vitamin C) designated as A.C.S reagent grade 99.1%pure from Aldrich Chemical Company and silica gel from FischerScientific International, Inc., designated as S8 32-1, 40 of Grade of 35to 70 sized mesh. Other similar sizes of silica gel also are effective,provided that the particle size and the pore size within the particlesare similar.

The silica gel was moistened with a saturated solution of ascorbic acidthat had been prepared by mixing up to 35% by weight ascorbic acid inwater, stirring, and straining the water/ascorbic acid mixture throughthe silica gel, followed by draining. It has been found that theconversion of NO₂ to NO proceeds well when the silica gel coated withascorbic acid is moist. The conversion of NO₂ to NO does not proceedwell in an aqueous solution of ascorbic acid alone.

The cartridge filled with the wet silica gel/ascorbic acid was able toconvert 1000 ppm of NO₂ in air to NO at a flow rate of 150 ml perminute, quantitatively, non-stop for over 12 days. A wide variety offlow rates and NO₂ concentrations have been successfully tested, rangingfrom only a few ml per minute to flow rates of up to 5,000 ml perminute. Using an annular cartridge, flow rates of up to 60,000 ml perminute have been used. The reaction also proceeds using other commonantioxidants, such as variants of vitamin E (e.g., alpha tocopherol andgamma tocopherol).

The antioxidant/surface-active material GENO cartridge may be used forvarious therapies. In one such example, the GENO cartridge may be usedas a NO₂ scrubber for NO inhalation therapy that delivers NO from apressurized bottle source. The GENO cartridge not only scrubs the NO₂but converts the NO₂ back into NO gas, which is then inhaled by thepatient. This cartridge is also referred to as a recuperator. This GENOcartridge may be used to help ensure that no harmful levels of NO₂ areinadvertently inhaled by the patient. Additionally, the GENO cartridgeensures that the patient is receiving the entire NO dose as NO gas andnot as the toxic form, NO₂.

According to one embodiment, a therapeutic composition is a mixture of asurface-activated material such as, but not limited to, silica gel andone or more suitable thermoplastic resins that are sintered at hightemperatures to form a porous solid matrix. The polymers include, butare not limited to, polyethylene, polypropylene or any thermoplasticresin that can be ground into a fine powder and the poured into a moldand sintered at high temperature to form a porous solid matrix. Thethermoplastic resin, when cured, provides a rigid porous structure withthe surface-activated material embedded in the pores. Additionally, thepolymer may be shaped or molded into any form.

According to one embodiment, the porous solid matrix is composed of atleast 20% silica gel. In another embodiment, the porous solid matrixincludes approximately 20% to approximately 60% silica gel. In yetanother embodiment, the porous solid matrix is composed of 50% silicagel. As those skilled in the art will appreciate, any ratio of silicagel to thermoplastic resin is contemplated so long as the mechanical andstructural strength of the porous solid matrix is maintained. In oneembodiment, the densities of the silica gel and the polymer aregenerally similar in order to achieve a uniform mixture and, ultimately,a uniform porous solid matrix.

According to one method, the solid matrix is formed by mixing silica gelwith a thermoplastic resin. The mixture is then sintered at a hightemperature to form a porous solid matrix and allowed to cool. After theporous solid matrix is formed, the porous solid matrix is flushed withan antioxidant solution. In one embodiment, the antioxidant solution isapproximately 20% ascorbic acid in water. Alternatively, ascorbic acidmay be substituted with other antioxidants such as, but not limited to,alpha tocopherol or gamma tocopherol. In other embodiments, theantioxidant solution may have varying antioxidant concentrations.Dissolved gases (e.g., oxygen and air) are excluded from the antioxidantsolution in order to prevent the formation of microscopic gas bubblesaround the solid polymer/silica gel matrix. The gas bubbles would alterthe surface chemistry and would prevent NO₂ from interacting with theantioxidant liquid inside the silica gel.

Once the solid matrix has been flushed, the excess antioxidant solutionthat is not bound by the silica gel may be rinsed off in order tominimize the precipitation of excess antioxidant solution during thedrying step. According to one embodiment, the porous solid matrix isvacuum dried until the moisture content is reduced to approximately 30%.In alternate embodiments, the solid matrix may be dried to have anymoisture content ranging from approximately 1% to approximately 99%.During the drying process, precautions need to be taken to ensure thatoxygen is excluded. The dried, solid matrix is assembled into the bodyand flushed with inert gas before and during the sealing process. Oxygenis excluded from the manufacturing process and during storage in orderto prevent the ascorbic acid (or other antioxidants) from slowlyoxidizing to dehydro-ascorbic acid and other oxidation products duringlong-term storage. In another embodiment, the cartridge is dried untilthere is no detectable water present, and the cartridge is then sealedand packaged dry in a moisture-proof container. The dried cartridge isreconstituted into an active cartridge by exposing the cartridge towater prior to use.

Compositions capable of releasing NO are taught, for example in U.S.Pat. Nos. 7,425,218; 6,397,660; 6,200,558; 5,632,981; 5,525,357; and5,405,919, which are incorporated by reference herein.

NO can be released from certain devices, such as those taught in U.S.Application No. 61/090,617, which is incorporated by reference herein.For example, a light, portable device for delivering NO with air has thepotential to improve a patient's quality of life. The device may bepowered by a small, battery-driven pump or by patient inhalation (usingan inhaler used in a manner similar to smoking a cigar). Additionally, atreatment providing NO (e.g., converting N₂O₄ into NO) would be morecost effective than oxygen therapy.

Currently, approved devices and methods for delivering inhaled NO gasrequire complex and heavy equipment. NO gas is stored in heavy gasbottles with nitrogen and no traces of oxygen. The NO gas is mixed withair or oxygen with specialized injectors and complex ventilators, andthe mixing process is monitored with equipment having sensitivemicroprocessors and electronics. All this equipment is required in orderto ensure that NO is not oxidized into nitrogen dioxide (NO₂) during themixing process since NO₂ is highly toxic. However, this equipment is notconducive to use in a non-medical facility setting (e.g., combatoperations or remote wilderness) since the size, cost, complexity, andsafety issues restrict the operation of this equipment to highly-trainedprofessionals in a medical facility.

In contrast, the delivery devices disclosed herein are self-contained,portable systems that do not require heavy gas bottles, sophisticatedelectronics, or monitoring equipment. Additionally, the delivery devicesare easy to use and do not require any specialized training. Moreover,the delivery devices allow an individual to self-administer a NOtreatment. The delivery devices are also lightweight, compact, andportable. According to one embodiment, the NO delivery device is thesize of a cigar or a conventional inhaler for one-time use or short-termtreatments. Alternatively, the NO delivery device is a larger device,yet portable device that can deliver NO for longer periods of time.

Useful pharmacological agents can be provided by incorporating nitricoxide-releasing N₂O₂-functional groups into a biopolymer. Accordingly,the N₂O₂-functional group is “bound to the polymer” as that term hasbeen defined herein. The term NONOate is used herein as a shorthand torefer to the nitric oxide-releasing N₂O₂-group. It has been discoveredthat incorporation of a NONOate into a biopolymer provides abiopolymer-bound NONOate composition that can be applied withspecificity to a biological site of interest. Site specific applicationof the biopolymer-bound NONOate enhances the selectivity of action ofthe nitric oxide-releasing NONOate. If N₂O₂ functional groups attachedto the biopolymer are necessarily localized, then the effect of theirnitric oxide release will be concentrated in the tissues with which theyare in contact. If the biopolymer is soluble, selectivity of action canstill be arranged, for example, by attachment to or derivatization of anantibody specific to the target tissue. Similarly, attachment of N₂O₂groups to small peptides that mimic the recognition sequences of ligandsfor important receptors provides localized concentrated effect of nitricoxide release, as would attachment to oligonucleotides capable ofsite-specific interactions with target sequences in a nucleic acid.Other proteins, peptides, polypeptides, nucleic acids andpolysaccharides, including hormones and motility, chemotactic andextravasating factors or agents, can be similarly utilized.

By way of illustration, a piperazine monoNONOate derivative can becovalently attached to a polypeptide containing the IKVAV recognitionsequence important in tumor cell chemotaxis. Through retention of boththe capacity to regenerate NO as an antichemotactic agent and theaffinity of the IKVAV sequence for tumor cells and/or sites in thevascular and lymphatic systems where the tumor cells tend to attach,metastasis can be reduced or even prevented.

It is believed that longevity of nitric oxide release in thebiopolymer-bound NONOate compositions of the present invention is to beattributed both to the physical structure of the composition and toelectrostatic effects. Thus, it is believed that if the biopolymer is aninsoluble solid, N₂O₂-groups near the surface of the particle should beavailable for rapid release while those that are more deeply imbeddedare sterically shielded, requiring more time and/or energy for thenitric oxide to work its way into the medium. Unexpectedly, it has beenfound that increasing positive charge in the vicinity of anN₂O₂-functional group also tends to increase the half-life of nitricoxide generation. The mechanism of this rate retardation may beattributable simply to repulsive electrostatic interactions, i.e.,increasing the number of H⁺ positive charges in the vicinity of theN₂O₂-groups inhibits attack of positively charged H⁺ ions on theN₂O₂-functional group and slows the rate of its H⁺ catalyzeddecomposition. For example, by attaching amino groups to the polymericsupport that are capable of forming the nitric oxide-releasingN₂O₂-functional group on reaction with nitric oxide, partially convertedstructures can be produced on less-than-exhaustive treatment with nitricoxide that after exposure to water contain a large number of positivelycharged ammonium centers surrounding the N₂O₂-group thatelectrostatically inhibit the approach of H⁺ ions capable of initiatingnitric oxide loss from the nitric oxide-releasing N₂O₂-functional group.

The nitric oxide-releasing N₂O₂-functional groups that are bound to thebiopolymer generally are capable of releasing nitric oxide in an aqueousenvironment spontaneously upon contacting an aqueous environment, i.e.,they do not require activation through a redox reaction or electrontransfer such as is required for glyceryl trinitrate and sodiumnitroprusside. Some of the nitric oxide/nucleophile complexes useful inthe context of the present invention do require activation by particularmeans, but only as necessary to free the nitric oxide-releasingX[N(O)NO] group in the vicinity of the particular cells of interest. Asan example, covalent attachment of a protecting group to the anionic[N(O)NO]-function provides a means of postponing nitric oxide releaseuntil the molecule reaches an organ capable of metabolically removingthe protecting group. By choosing a protecting group that is selectivelycleaved by enzymes specific to a tumor, biological disorder, cell, ortissue of interest, for example, the action of the nitricoxide/nucleophile complex can be targeted to maximize the desiredeffect. While the biopolymer-bound NONOate compositions of the presentinvention are capable of releasing nitric oxide in an aqueous solution,such a compound preferably releases nitric oxide under physiologicalconditions.

For example, a NONOate functionality can be attached to a tumor-specificantibody or other protein which has one or more lysine side chain aminogroups that are unnecessary to the function of the protein by reactingsaid lysine group(s) with a derivatizing agent capable of covalentlyattaching first to the lysine amino nitrogen then in a subsequent stepto the sulfur atom of an O-functionalized NONOate containing a freethiol grouping elsewhere in the molecule. Once such a protein arrives atthe desired target tissue after systemic application, enzymatic orhydrolytic removal of the substituent bound to oxygen frees the anionicNONOate function to concentrate NO release at that site.

The preferred nitric oxide-releasing N₂O₂-functional group which is usedto form the biopolymer-bound NONOates of the present invention isdefined by the formula:

wherein X is an organic or inorganic moiety and X′ is an organic orinorganic substituent, a pharmaceutically acceptable metal center, apharmaceutically acceptable cation, or the like. The N₂O₂ ⁻ group isbonded to the biopolymer through either or both the linking groups X andX′. The nitric oxide-releasing N₂O₂-functional group is preferably anitric oxide/nucleophile adduct, e.g., a complex of nitric oxide and anucleophile most preferably a nitric oxide/nucleophile complex whichcontains the anionic moiety X[N(O)NO]⁻, where X is any suitablenucleophile residue. The nucleophile residue is preferably that of aprimary amine (e.g., X═(CH₃)₂CHNH, as in (CH₃)₂CHNH[N(O)NO]Na), asecondary amine (e.g., X═(CH₃CH₂)₂N, as in (CH₃CH₂)₂N[N(O)NO]Na), apolyamine (e.g., X=spermine, as in the zwitterion H₂N(CH₂)₃NH₂⁺(CH₂)₄N[N(O)NO]⁻(CH₂)₃NH₂, X=2-(ethylamino)ethylamine, as in thezwitterion CH₃CH₂N[N(O)NO]⁻CH₂CH₂NH₃ ⁺, orX=3-(n-propylamino)propylamine, as in the zwitterionCH₃CH₂CH₂N[N(O)NO]⁻CH₂CH₂CH₂NH₃ ⁺), or oxide (i.e., X═O⁻, as inNaO[N(O)NO]Na), or a derivative thereof. Such nitric oxide/nucleophilecomplexes are capable of delivering nitric oxide in a biologicallyusable form as a predictable rate.

The various embodiments described above are provided by way ofillustration only and should not be construed to limit the claimedinvention. Those skilled in the art will readily recognize variousmodifications and changes that may be made to the claimed inventionwithout following the example embodiments and applications illustratedand described herein, and without departing from the true spirit andscope of the claimed invention, which is set forth in the followingclaims.

What is claimed is:
 1. A method for delivering nitric oxide therapy to asubject comprising: exposing a composition including a nitric-oxidereleasing agent, silica, and an antioxidant to water in a chamber of agas delivery device that includes an inlet, an outlet, a particle filterat the outlet, and the chamber, wherein the nitric-oxide releasing agentis polymeric composition including a polymer and at least one nitricoxide releasing N₂O₂ ⁻ functional group, administering the gas deliverydevice to the subject; generating an air flow through the inlet, thecomposition in the chamber, and the outlet by subject inhalation; andreleasing a therapeutic amount of nitric oxide from the composition intothe air flow.
 2. The method of claim 1, wherein the silica preventstoxic compounds from entering the subject.
 3. The method of claim 2,wherein the antioxidant is ascorbic acid, alpha tocopherol, or gammatocopherol.
 4. The method of claim 1, wherein the composition is anointment.
 5. The method of claim 1, wherein the composition isincorporated into an adhesive strip.
 6. The method of claim 5, whereinthe adhesive strip has a calibrated scale on one surface thereof foraccurate measurement of an ointment dosage.
 7. The method of claim 1,wherein the composition is in the form of a gum or lozenge.
 8. Themethod of claim 1, wherein the delivery device is an inhaler or nasalcartridge.
 9. The method of claim 1, further comprising a foil backing.10. The method of claim 5, wherein the foil backing prevents nitricoxide from being released into an external environment.
 11. The methodof claim 1, wherein the therapeutic amount of nitric oxide is at least 1ppm.
 12. The method of claim 1, wherein the therapeutic amount of nitricoxide is at least 100 ppm.
 13. The method of claim 1, wherein thetherapeutic amount of nitric oxide is at least 200 ppm.
 14. The methodof claim 1, wherein the therapeutic amount of nitric oxide is at least300 ppm.